DEM

http://nsidc.org/data/docs/daac/nsidc0304_0305_glas_dems/GLAS_Antarctic_DEM.jpg

DEM, or digital elevation model, is a computer based model that can be either 2D or 3D model of a certain terrain. It is used on things like the terrain of the Earth, the moon, or asteroids to better understand the surface of these things. The DEM above is based on the antarctic and shows projected elevation in that region.